#include <Wire.h>
#include <LiquidCrystal_I2C.h>

LiquidCrystal_I2C lcd(0x27, 20, 4); 
 
#define TRIG_PIN 5
#define ECHO_PIN 18
#define SOUND_SPEED 0.0343

float cm;

long leituraDistanc(int trigPin, int echoPin) {
  pinMode(trigPin, OUTPUT);
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  pinMode(echoPin, INPUT);
  return pulseIn(echoPin, HIGH);
}

void setup() {
  Serial.begin(115200);

  // Configura I2C para ESP32
  Wire.begin(21, 22);  

  lcd.init();
  lcd.backlight();
  lcd.print("--> Distancia <--");
  delay(3000);
  lcd.clear();
}

void loop() {
  cm = (SOUND_SPEED * leituraDistanc(TRIG_PIN, ECHO_PIN)) / 2;

  lcd.setCursor(0, 0);
  lcd.print("Distancia:");

  lcd.setCursor(0, 1);
  lcd.print(cm, 1);
  lcd.print(" cm");

  delay(1000);
  lcd.clear();
}